I have eaten there several times. I recommend strongly. I took my parents a few months ago.
First, I recommend taking the time to go to the pinnacle park thing at the top of Yerba Buena (one might think of it as part of TI, but TI is the manufactured flat part). The view is even more exceptional than everywhere else. There’s not much to do there besides the view, but, oh, the view. [ I talked to a cyclist, older fellow from Berkeley, he said twice a week he crosses the bridge and comes up the hill, for a lark ]
Oh, you can also get to TI by ferry these days. The schedule seems a bit hit or miss, but it would be a fun day trip. You can take the bus but its less fun. I think there are also on-demand water taxis plying the little few hundred yards?
Mersea. If you get a table along the front, in one of the two containers or the little patio, it’s a pretty cool spot. There’s something more like overflow seating in the center courtyard, which defeats a bit of the point, the view is so blocked you could be almost anywhere. The “good seats” are mostly (cramped) 4 tops except for one kind of corner booth that would hold more - or maybe push together the “ouside courtyard” tables". But 4 or less you’ve got a chance. The most recent time I was there, there was a private party (wedding rehearsal) that had bought out about half the space. We started at the “courtyard” and I watched the “good seats” like a hawk and pounced, so we had our actual meal with the view.
The food is pretty good, but it’s a super limited menu. The winner was the fried fish, in sandwich form or fish and chips form. It was as good as I’ve had: perfectly cooked (not overcooked), fresh fish, not too much batter, but not too little, good bun, good toppings. Everything else seemed well executed.
They seem to push the alcohol a bit which would make for a good boozy late afternoon stop. Not a broad bar, but things like negronis and spritzes, and a modest beer by the can selection. I wasn’t in that mode.
There was a small jazz combo in the courtyard that wasn’t bad. A little loud (as usual) and I mentioned the courtyard had no view. When I showed up they were finishing, played a couple tunes, packed up.
Would recommend because the view is oh la la, problem is no plan B if there aren’t seats.